goes in to safe mode when throttle snaps shut...

[Super73]

I have been helping a friend get his vette dialed in. It ran perfect with the LS6 intake / LS6 DBW TB. He decided to send the manifold off to have the 78mm cut off and a 90 put on. He said while driving it around it would go in to safe mode from time to time.

We decided to put it on the dyno and after the 3rd pull it went in to safe mode but had a clean dyno graph and pull.. Didn't figure out why right away. Made the 4rth pull all was fine. 5th pull and again in safe mode (by this time AFR was dead on car was making solid power). But I relized it was going in to safe mode when he lifted, as if lifting to fast was causing it.

Took it out on the street and did some testing. Sure enough, if you go to shift quick and bang the next gear, when the TB blade closes too quick, it goes in to safe mode. I could ring 1st 2nd 3rd and as long as i didn't get off the throttle real fast, it would be fine. But who wants to granny shift a car making decent power?

Any ideas what area might need adjusting?

I can't remember exact year right now and I don't have the file on me, at school and thought I'd get the ball rolling. But i figure there is some general info that might help. Thanks in advance.


Shaun

[Super73]

No one has any ideas?

[Bill@HPTuners]

any dtc's?

[Super73]

It popped one while doing it and I disabled it. I can't remember if it was 1515, 1516, 1517, or 1518 but i set them all to "no error reported" and unchecked SES.. Still doing it.

[mowton]

1514 would make sense...TPS vs g/cyl. Log the TPS% and Dyn Cyl air and check against the values in Eng Diagnostics>General>TPS. Adjust with some safety margin.

Ed M

[Higgs Boson]

I had to disable 1514 while tuning then log tps data and adjust the table and then reenable 1514.